Valproate and Warfarin: Drug Interaction Guide
Quick answer: This combination requires caution. Valproate and Warfarin can be used together with adjustments and monitoring.
How Valproate interacts with Warfarin
Valproate displaces warfarin from albumin binding sites and may inhibit CYP2C9 metabolism, increasing free warfarin and elevating INR.
What you should do
Monitor INR within one week of initiating or stopping valproate. Anticipate possible warfarin dose reduction of 10-25%.
Key facts
Severity
Moderate — caution required
Mechanism
Valproate displaces warfarin from albumin binding sites and may inhibit CYP2C9 metabolism, increasing free warfarin and ...
Action
Monitor INR within one week of initiating or stopping valproate. Anticipate possible warfarin dose reduction of 10-25%.
Frequently asked questions
Can I take Valproate and Warfarin together?
With caution. Monitor INR within one week of initiating or stopping valproate. Anticipate possible warfarin dose reduction of 10-25%.
What is the severity of this interaction?
The interaction between Valproate and Warfarin is classified as Moderate — caution required. Valproate displaces warfarin from albumin binding sites and may inhibit CYP2C9 metabolism, increasing free warfarin and elevating INR.
What should I do if I'm prescribed both?
Monitor INR within one week of initiating or stopping valproate. Anticipate possible warfarin dose reduction of 10-25%. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.